Thread: lithium ?
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Old 10-25-2019, 03:46 PM   #37
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City: New Orleans
Country: USA
Vessel Name: Stella
Vessel Model: Seaton 56
Join Date: Sep 2017
Posts: 81
Interesting thread as I have been evaluating a LiFePO4 bank for several weeks.

The boat has an (overly)complex, but flexible, DC system. In fact I just wrote, and then deleted, a lengthy description - too much detail for casual reading. Cutting to the bottom line:

We need new house batteries. During our last cruise (5 months, Bahamas, mostly at anchor) the batteries became increasingly resistant to charge rates and quickly discharged to lower voltages.

I would replace the house batteries (5 x 250 AH AGM's) with 3 x Victron 200 AH LiFePO4's. These are the easiest fit from size/weight/capacity viewpoints.

What I'm struggling with is the need for new charging and control equipment. Vendors, of course, recommend an entirely new system. I would like to use what I have, otherwise it becomes significantly more expensive.

> MS2812 Magnum Charger/Inverter with battery monitor kit and ME-RC remote controller. Charges at maximum 125 amps.
> A 160 amp Leece-Neville alternator with 3-stage Heart regulator.

I am considering:

> An external battery management system (probably Victron BMS 12/200) as the Victron batteries do not have an internal BMS.
> Upgrade the Magnum ME-RC controller to the ME-ARC controller as it has significantly more options to control the charger.
> A new alternator regulator which could fit the LiFePO4 charge profile and unload the alternator if it overheated.

Even these upgrades will probably cost ~$1K but would save the cost of a new inverter/charger, controller and shunt.

We will also evaluate PV panels after the battery system is implemented.

Any experience or thoughts are appreciated.
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